The present invention is directed to a polarized magnetic relay having a base body; a coil being secured in the base body and having a coil body with an axially extending passage, a first end flange, a second end flange and a winding on the coil between the flanges; a bar-shaped armature being received inside of the passage of the coil body on an axis thereof with one end being pivotally mounted adjacent the first flange so that the armature can pivotably move in the coil body, a permanent magnet arrangement having two pole plates which are on a common plane extending parallel to the coil axis, each pole plate adjacent the second flange having end portions extending at right angles to the common plane to provide spaced surfaces forming an air gap therebetween with a free end of the armature extending therethrough, said magnet arrangement including a flux plate having a portion extending perpendicular to the coil axis and having at least one segment extending parallel to the pole plates and coacting with the pole plates to form a space for receiving each magnet of the arrangement; at least one stationary contact element anchored in the base body and at least one movable contact element being moved by the armature between a position out of engagement with the associated stationary contact and a position engaging the stationary contact.
A relay of the above known type is disclosed in U.S. patent application Ser. No. 401,235, filed July 23, 1982, which application was based on German Letters Patent No. 31 32 244. The disclosure of this copending application was issued on April 2, 1985 as U.S. Pat. No. 4,509,025 and is incorporated by reference thereto. As disclosed in this patent application, the relay system is very sensitive and has a particular advantage that both a monostable as well as a bistable switching characteristic can be achieved without structural modifications by means of corresponding adaptation of the quadripole permanent magnet system whereby a response value can be obtained in a very tight tolerance range.
The system described in the patent application is particularly suited for very small relays having more than one changeover contact so that a very compact structure is possible. The arrangement of the quadripole permanent magnet over the coil given simultaneous coverage of the contact elements by the pole plates or, respectively, yokes, is very meaningful to design this relay for a compact structure. This design, however, involves problems when such a system is to be utilized for switching high currents because an insulating path required between the contact elements and the magnet system necessitates additional measures. Further, without increasing the overall height, the flat magnet arrangement employed therein can be practically executed only with a ceramic magnet whose response to temperatures will lead to a great reduction of the contact force given uses under high ambient temperatures.